I started a bounty and was on step 3, wrote up a nice little description of my bounty, and then I accidentally clicked on the background of the site which caused the DHTML popup to go away with prompting me. It wasn't a ton of text, but I lost what I wrote and ended up just deciding not to write anything the second time around.

Suggestion: add a prompt asking the user if they want to cancel or only close the dialog if a close/cancel button is explicitly clicked.